As disclosed, for example, in US 2010/0090526 corresponding to JP-A-2010-90874, a vehicle equipped with an automatic engine stop/start (i.e., stop/restart) system (so-called idle-stop system or idle-reduction system) has already been proposed. The idle-stop system automatically stops an engine of the vehicle when a predetermined automatic stop condition is met, and automatically restarts the engine when a predetermined automatic start condition is met.
The vehicle disclosed in US 2010/0090526 has two energization circuits for energizing an electrical load to drive an engine starter.
One energization circuit (hereinafter referred to as the “auto-start circuit”) is used to automatically restart the engine, which was automatically stopped by a function of the idle-stop system, by the function. The other energization circuit (hereinafter referred to as the “user-start circuit”) is used to start the engine in response to a start-up operation performed by a driver of the vehicle. That is, the user-start circuit is used when the driver starts the engine with his/her own intention. The duplication of energization circuits provides redundancy and improves reliability. Further, even when a power supply voltage is low, the user-start circuit allows the driver to start the engine.
In a vehicle equipped with an idle-stop system, it is important to check whether such an auto-start circuit works normally (i.e., whether the auto-start circuit energizes the electrical load of the starter normally) before the engine is automatically stopped.
Whether or not the auto-start circuit works normally can be determined by actually causing the auto-start circuit to work. However, the auto-start circuit cannot energize the electrical load when there is no need to drive the engine.
Therefore, in a conventional engine starter controller, a failure in an auto-start circuit cannot be detected until the auto-start circuit actually works upon satisfaction of the automatic start condition after the engine, which is started in response to the user start-up operation, is automatically stopped.